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<table width="100%" summary="page for epilepsy"><tr><td>epilepsy</td><td align="right">R Documentation</td></tr></table>

<h2> Epilepsy Data </h2>

<h3>Description</h3>


<p>A randomised clinical trial investigating the effect of an anti-epileptic
drug.
</p>


<h3>Usage</h3>

<pre>data("epilepsy")</pre>


<h3>Format</h3>


<p>A data frame with 236 observations on the following 6 variables.
</p>

<dl>
<dt><code>treatment</code></dt><dd><p>the treatment group, a factor with levels <code>placebo</code>
and <code>Progabide</code>.</p>
</dd>
<dt><code>base</code></dt><dd><p>the number of seizures before the trial.</p>
</dd>
<dt><code>age</code></dt><dd><p>the age of the patient.</p>
</dd>
<dt><code>seizure.rate</code></dt><dd><p>the number of seizures (response variable).</p>
</dd>
<dt><code>period</code></dt><dd><p>treatment period, an ordered factor with levels
<code>1</code> to <code>4</code>.</p>
</dd>
<dt><code>subject</code></dt><dd><p>the patient ID, a factor with levels <code>1</code> to
<code>59</code>.</p>
</dd>
</dl>



<h3>Details</h3>


<p>In this clinical trial, 59
patients suffering from epilepsy were randomized to groups receiving either 
the anti-epileptic drug Progabide or a placebo in addition to 
standard chemotherapy. The numbers of seizures suffered in each 
of four, two-week periods were recorded for each patient along 
with a baseline seizure count for the 8 weeks prior to being 
randomized to treatment and age. The main question of interest 
is whether taking progabide reduced the number of epileptic seizures  
compared with placebo.
</p>


<h3>Source</h3>


<p>P. F. Thall and S. C. Vail (1990),
Some covariance models for longitudinal count data with
overdispersion. <EM>Biometrics</EM>, <B>46</B>, 657&ndash;671.
</p>


<h3>Examples</h3>

<pre>

  data("epilepsy", package = "HSAUR")
  library(lattice)
  dotplot(I(seizure.rate / base) ~ period | subject, data = epilepsy, 
          subset = treatment == "Progabide")
  dotplot(I(seizure.rate / base) ~ period | subject, data = epilepsy, 
          subset = treatment == "Progabide")

</pre>


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